The long range aim of this research is to study the role of endogenous chemical substrates found in brain in the regulation of conditioned behavior. The present objective is to study the relationship between catecholamines and operant behavior. Studies are planned in which brain chemistry will be altered by both drugs and natural precursors and the effects on operant behavior will be measured; in other studies catecholamine turnover will be measured as a function of the behavior in which the animal is engaged. To these ends a variety of techniques will be employed. These include: operant behavior studies, measurement of catecholamine level and turnover as well as computer analysis of data.